Modelización e integración de sistemas de adquisición de datos inteligentes en sistemas de instrumentación para dispositivos de fusión

La obtención de energía a partir de la fusión nuclear por confinamiento magnético del plasma, es uno de los principales objetivos dentro de la comunidad científica dedicada a la energía nuclear. Desde la construcción del primer dispositivo de fusión, hasta la actualidad, se han llevado a cabo multitud de experimentos, que hoy en día, gran parte de ellos dan soporte al proyecto International Thermonuclear Experimental Reactor (ITER). El principal problema al que se enfrenta ITER, se basa en la monitorización y el control del plasma. Gracias a las nuevas tecnologías, los sistemas de instrumentación y control permiten acercarse más a la solución del problema, pero a su vez, es más complicado estandarizar los sistemas de adquisición de datos que se usan, no solo en ITER, sino en otros proyectos de igual complejidad. Desarrollar nuevas implementaciones hardware y software bajo los requisitos de los diagnósticos definidos por los científicos, supone una gran inversión de tiempo, retrasando la ejecución de nuevos experimentos. Por ello, la solución que plantea esta tesis, consiste en la definición de una metodología de diseño que permite implementar sistemas de adquisición de datos inteligentes y su fácil integración en entornos de fusión para la implementación de diagnósticos. Esta metodología requiere del uso de los dispositivos Reconfigurable Input/Output (RIO) y Flexible RIO (FlexRIO), que son sistemas embebidos basados en tecnología Field-Programmable Gate Array (FPGA). Para completar la metodología de diseño, estos dispositivos van a ser soportados por un software basado en EPICS Device Support utilizando la tecnología EPICS software asynDriver. Esta metodología se ha evaluado implementando prototipos para los controladores rápidos de planta de ITER, tanto para casos prácticos de ámbito general como adquisición de datos e imágenes, como para casos concretos como el diagnóstico del fission chamber, implementando pre-procesado en tiempo real. Además de casos prácticos, esta metodología se ha utilizado para implementar casos reales, como el Ion Source Hydrogen Positive (ISHP), desarrollada por el European Spallation Source (ESS Bilbao) y la Universidad del País Vasco. Finalmente, atendiendo a las necesidades que los experimentos en los entornos de fusión requieren, se ha diseñado un mecanismo mediante el cual los sistemas de adquisición de datos, que pueden ser implementados mediante la metodología de diseño propuesta, pueden integrar un reloj hardware capaz de sincronizarse con el protocolo IEEE1588-V2, permitiendo a estos, obtener los TimeStamps de las muestras adquiridas con una exactitud y precisión de decenas de nanosegundos y realizar streaming de datos con TimeStamps. ABSTRACT Fusion energy reaching by means of nuclear fusion plasma confinement is one of the main goals inside nuclear energy scientific community. Since the first fusion device was built, many experiments have been carried out and now, most of them give support to the International Thermonuclear Experimental Reactor (ITER) project. The main difficulty that ITER has to overcome is the plasma monitoring and control. Due to new technologies, the instrumentation and control systems allow an approaching to the solution, but in turn, the standardization of the used data acquisition systems, not only in ITER but also in other similar projects, is more complex. To develop new hardware and software implementations under scientific diagnostics requirements, entail time costs, delaying new experiments execution. Thus, this thesis presents a solution that consists in a design methodology definition, that permits the implementation of intelligent data acquisition systems and their easy integration into fusion environments for diagnostic purposes. This methodology requires the use of Reconfigurable Input/Output (RIO) and Flexible RIO (FlexRIO) devices, based on Field-Programmable Gate Array (FPGA) embedded technology. In order to complete the design methodology, these devices are going to be supported by an EPICS Device Support software, using asynDriver technology. This methodology has been evaluated implementing ITER PXIe fast controllers prototypes, as well as data and image acquisition, so as for concrete solutions like the fission chamber diagnostic use case, using real time preprocessing. Besides of these prototypes solutions, this methodology has been applied for the implementation of real experiments like the Ion Source Hydrogen Positive (ISHP), developed by the European Spallation Source and the Basque country University. Finally, a hardware mechanism has been designed to integrate a hardware clock into RIO/FlexRIO devices, to get synchronization with the IEEE1588-V2 precision time protocol. This implementation permits to data acquisition systems implemented under the defined methodology, to timestamp all data acquired with nanoseconds accuracy, permitting high throughput timestamped data streaming.

Los árboles singulares en el paisaje. Propuesta de un modelo para su evaluación: el caso del territorio histórico de Álava

La Tesis Doctoral que se presenta trata de profundizar en el conocimiento del patrimonio arbóreo, en la cuestión de la evaluación y la singularidad a nivel de ejemplares y agrupaciones. La metodología incorpora nuevas herramientas, modelos y criterios utilizados en la valoración del paisaje y de los recursos naturales. Siendo el árbol un generador de espacio y habitats, solo o en masa, es vínculo entre la naturaleza y el ser humano, las comunidades y sus costumbres. Desde estos parámetros se indagan los procesos que permiten estimar el significado, la importancia y el valor del árbol para llevarlo a una consideración de Singular y/o Monumental. El estudio se basa en los sistemas de catalogación, tras el reconocimiento, localization y selección de ejemplares. Así mismo, se explora la relación sistémica entre árbol y entorno para poner de relieve la importancia del árbol en la configuración de determinados paisajes culturales y ecológicos -como son los robledales de antiguos trasmochos en Euskadi-. Sobre un primer inventario se realiza un estudio pormenorizado de cada árbol registrado y, en un procedimiento paramétrico, se definen criterios -ecológicos y paisajísticos, etnográficos y culturales- de selección de elementos y de evaluación. La obtención de distintos índices de singularidad para los árboles, utilizando modelos tanto cualitativos como cuantitativos, sirve como vía hacia una categorization de los árboles muestreados. A partir de la figura de "Árbol Singular", recogida en la Ley 16/ 1994, de Conservación de la Naturaleza del País Vasco se realiza una revisión del marco legislativo y el régimen de protección, haciendo un análisis a nivel local, autonómico y estatal. Dicho examen pone de manifiesto la diversidad de contextos y significados bajo los que se presentan los árboles. Se muestra también una (in)definición: cierta ambigüedad en torno a la definición que induce a diferentes interpretaciones y nomenclaturas en un intento de delimitar la categoría para regularlo jurídicamente. Estas figuras concebidas desde las políticas de protección ambiental, no siempre resultan del todo efectivas. El Catálogo de Árboles Singulares del País Vasco, creado por Decreto como instrumento para poner en valor estos recursos naturales, no ha sido actualizado desde hace casi veinte años. Sin embargo, se han llevado a cabo iniciativas de ampliación como el trabajo impulsado por el Departamento de Medio Ambiente y Biodiversidad de la Diputación Foral de Álava para el inventario de los árboles singulares del Territorio Histórico de Álava y la propuesta de catálogo a partir del cual se desarrolla esta Tesis Doctoral. Desde estas reflexiones y el desarrollo de modelos para la evaluación y catalogación de los ejemplares registrados, la investigación trata de descifrar cómo observamos a los árboles con los que nos vinculamos, cómo son identificados, a través de qué otros parámetros intangibles les damos valor, y por qué necesitamos clasificarlos. El trabajo concluye con propuestas y acciones alternativas para la conservación y mejora de los árboles que se proponen como singulares, entre ellas, la divulgación y la sensibilización para garantizar el compromiso y la ampliación en el futuro de un catálogo abierto para los árboles de interés. ABSTRACT The PhD thesis here presented tries to deepen the knowledge of tree heritage, the issue of evaluation and singularity where it comes to either specimen or groups. The methodology includes new tools, models and criteria to be used in the assessment of landscape and natural resources. With the tree being a creator of space and habitats, alone or in groups, it is a link between nature and humans, societies and their habits. Using these parameters processes are being sought after: processes that allow us to assess the meaning, the importance and the value of trees in order to lead us to considering a tree as being a 'Singular tree' and/or 'Heritage tree'. The research is based on cataloging systems, after recognizing, localizing and selecting of specimen. This way, the systemic relation between the tree and its surrounding is being explored to get a view on the importance of trees in certain cultural and ecological landscapes -such as the oak fields consisting of ancient pollards in the Basque Country-. After a first inventory a detailed study is performed of each registered tree and, using a parametric method, criteria for selection of elements and evaluation are defined -ecological and those concerning the landscape, as well as ethnographical and cultural-. The creation of different indexes of singularity for trees, using qualitative as well as quantitative models, serves as a way to categorize the selected trees. A revision is done on legislation and the protection regimen, analyzing on a local, autonomic state and national level, parting from the concept of the Singular Tree, as included in the Law 16/1994, of Nature Conservation of Basque Coutry. This review proves the diversity of contexts and meanings in which the trees are being presented. Also an (un)definition appears; certain ambiguity of the definition which induces different interpretations and nomenclatures in an attempt to limit categorization in order to legally regulate. These concepts created out of environment protection politics do not always turn out to be completely effective. The Catalogue of Singular Trees in the Basque Country, created by decree as an instrument to value these natural resources, has not been updated since almost twenty years. However, there have been initiatives of amplification such as the work promoted by the Environment and Biodiversity Service of Provincial Council of Alava to create the inventory of singular trees of the Historical Territory of Álava and the catalogue proposal which forms the starting point of this PhD thesis. Parting from these considerations and the development of models for evaluation and cataloging of the registered specimen, the investigation attempts to unravel the way we observe the trees with which we link, how they are identified, by which intangible parameters we assess them and why we need to classify them. This study ends with proposals and alternative actions for the conservation and improvement of the trees that are being proposed as being singular. Among them are the publication and creating of awareness to guarantee the commitment and the development of an open catalogue for significant trees.

Eduardo Chillida, arquitecto

Es sabido que tras abandonar la carrera de arquitectura Chillida marcha a Paris a comenzar su carrera como escultor. De vuelta al País Vasco el hierro es el material en el que encuentra un camino propio. Toda la obra de su primera década está muy alejada en el aspecto formal de la arquitectura. Sin embargo, las líneas de fuerza que los hierros configuran muestran un interés espacial que queda manifiesto en una obra de 1953 denominada Consejo al espacio I. A partir de aquí su obra gira en torno al vacío. Las formas cambiarán con los materiales pero no el propósito. En sus dibujos, las manos expresan, más allá de su condición figurativa, la búsqueda del espacio cóncavo que los dedos encierran. El espacio que encuentra en la palma de la mano es equivalente al que construye con dedos gigantes de madera u hormigón. Chillida observa sus obras con una mirada cuya idea de escala se distancia del concepto de dimensión. Adquieren así una posibilidad de crecer que facilita imaginar sus espacios como arquitectura. Tras el hierro, el trabajo en madera y alabastro aproxima -en el aspecto formal- la obra de Chillida a la arquitectura. Los títulos de numerosas obras hacen referencia a ella o a conceptos con ella relacionados. Elogio de la arquitectura, Homenaje a la arquitectura, Arquitectura heterodoxa, Modulación del espacio, construcción heterodoxa, Alrededor del vacío, Mesa del arquitecto o Casa de luz, son algunos de ellos. La introducción del vacío en el alabastro da comienzo a un proceso tendente a que el espacio interior tenga una importancia inversamente proporcional a su presencia en la forma exterior. Un proceso de progresivo hermetismo donde pequeños espacios interiores son expresados mediante grandes masas envolventes. El espacio interior es el principal motivo por el que vemos la obra de Eduardo Chillida como arquitectura. La condición de interior, apreciable igualmente en sus grandes obras en el espacio público, hace que estas no constituyan únicamente hitos visuales sino espacios de protección con los que cuerpo interactúa estableciendo una nueva relación con el paisaje, el horizonte o el cosmos. La búsqueda de un interior vacío tiene como consecuencia la evolución hacia la desaparición de la forma exterior. Tal evolución comienza con el diálogo entre el bolo natural de alabastro y el vacío tallado de Homenaje a Goethe, y, como muestra de la inter-escalabilidad de la obra de Chillida, concluye con la introducción de un vacío oculto en la montaña sagrada de Tindaya. El gran vacío de Tindaya nos hace mirar la obra de pequeño formato a través de su filtro de aumento. Nos permite entender que el límite entre arquitectura y escultura es difuso en la obra del escultor vasco. Que la arquitectura puede estar en el origen de su escultura. Que su escultura puede ser el germen de muchas arquitecturas. ABSTRACT It is well known that after leaving his architectural studies Chillida went to Paris in order to begin his career as a sculptor. Back again to the Basque Country, iron is the material in which he finds his own way. In terms of form, his work from the very first ten years is far away from architecture. However, the strength lines set by the iron show a spatial will that is clearly evident in a 1953 piece called Advice to space I. From there on, his work focuses on void. Different materials will set different forms but the purpose will remain the same. In his drawings, hands are expressing, beyond its figurative condition, the search of the concave space that fingers are enclosing. The space founded in the palm of the hand is equivalent to the one built with giant wood or concrete fingers. Chillida faces his work with a look where the idea of scale takes distance to the concept of dimension. His works gets then a possibility to grow that allow us to imagine his spaces as architecture. Following iron, wood and alabaster pieces, in the formal aspect, approaches Chillida´s work to architecture. The titles of many sculptures are referred to it or to the concept related to it. In praise of architecture, Homage to architecture, Heterodox architecture, Modulation of space, Heterodox construction, Around the void, Architect’s table, or House of light, are some of them. The introduction of void in alabaster begins a process leading to the interior space has a presence inversely proportional to its importance in the external form. A process of progressive secrecy where small interior spaces are expressed through large enveloping masses. The interior space is the main reason why we see the work of Eduardo Chillida as architecture. The condition of inner space, equally noticeable in his great works in public space, makes this not only constitute visual landmarks, but protection spaces that body interacts with establishing a new relationship with the landscape, the horizon or the cosmos. The search of an inner void leads to an evolution towards the disappearance of the external form. The evolution begins in the dialogue between the natural bolus of alabaster and the carved void of Homage to Goethe, and as a sign of inter-scalability of the work of Chillida, it concludes with the introduction of a hidden void in the sacred mountain of Tindaya. The great void of Tindaya makes us look at a small format work trough the filter of his increase filter. It allows us to understand that the boundary between architecture and sculpture is diffuse in the work of the Basque sculptor. That architecture can be at the origin of his sculpture. That his sculpture may be the seed of many architectures.

How do primary health care teams learn to integrate intimate partner violence (IPV) management? A realist evaluation protocol

Background: Despite the existence of ample literature dealing, on the one hand, with the integration of innovations within health systems and team learning, and, on the other hand, with different aspects of the detection and management of intimate partner violence (IPV) within healthcare facilities, research that explores how health innovations that go beyond biomedical issues—such as IPV management—get integrated into health systems, and that focuses on healthcare teams’ learning processes is, to the best of our knowledge, very scarce if not absent. This realist evaluation protocol aims to ascertain: why, how, and under what circumstances primary healthcare teams engage (if at all) in a learning process to integrate IPV management in their practices; and why, how, and under what circumstances team learning processes lead to the development of organizational culture and values regarding IPV management, and the delivery of IPV management services. Methods: This study will be conducted in Spain using a multiple-case study design. Data will be collected from selected cases (primary healthcare teams) through different methods: individual and group interviews, routinely collected statistical data, documentary review, and observation. Cases will be purposively selected in order to enable testing the initial middle-range theory (MRT). After in-depth exploration of a limited number of cases, additional cases will be chosen for their ability to contribute to refining the emerging MRT to explain how primary healthcare learn to integrate intimate partner violence management. Discussion: Evaluations of health sector responses to IPV are scarce, and even fewer focus on why, how, and when the healthcare services integrate IPV management. There is a consensus that healthcare professionals and healthcare teams play a key role in this integration, and that training is important in order to realize changes. However, little is known about team learning of IPV management, both in terms of how to trigger such learning and how team learning is connected with changes in organizational culture and values, and in service delivery. This realist evaluation protocol aims to contribute to this knowledge by conducting this project in a country, Spain, where great endeavours have been made towards the integration of IPV management within the health system.

Acciones públicas de sensibilización de género: el esfuerzo de la administración regional y local en comunicación publicitaria (1999-2007)

El artículo analiza las iniciativas de comunicación relacionadas con la igualdad de oportunidades entre mujeres y hombres. El objetivo es analizar con enfoque de género las acciones realizadas por parte de las instituciones públicas regionales y locales para sensibilizar y promover la conciliación entre la vida familiar y laboral de seis comunidades autónomas (Andalucía, Cataluña, Comunidad Valenciana, Galicia, Madrid y País Vasco) y de sus capitales, desde 1999 (cuando se aprueba la ley de conciliación) hasta 2007 (se aprueba la ley de igualdad). La información sobre publicidad convencional fue proporcionada por Infoadex. Para la recogida de otro tipo de iniciativas a través de medios menos convencionales se acudió a cuatro fuentes institucionales: 1) Ayuntamientos de las capitales, como fuente estrictamente local, 2) Diputaciones de la capital de la Comunidad Autónoma, como fuente provincial, 3) Direcciones Generales de la Mujer o instituciones análogas como fuente de información a nivel regional o autonómico y, por último, 4) otras concejalías vinculadas al tema de la corresponsabilidad, cuyo radio de acción también es autonómico. Los resultados, aunque con diferencias entre regiones, reflejan carencias en la cobertura de las acciones que llevan a cuestionar la falta de estrategia política en términos de comunicación, pese a la introducción sistemática de estos objetivos en la agenda internacional (ONU y UE) y del gobierno español. En consecuencia, las campañas publicitarias e iniciativas recogidas contribuyen a la visibilización del problema y al empoderamiento, pero no tanto al objetivo de la paridad.

Enantioselective Michael addition of isobutyraldehyde to nitroalkenes organocatalyzed by chiral primary amine-guanidines

Primary amine-guanidines derived from trans-cyclohexane-1,2-diamines are used as organocatalysts for the enantioselective conjugate addition of isobutyraldehyde to arylated and heteroarylated nitroalkenes. The reaction was performed in the presence of imidazole as the additive in aqueous DMF as the solvent at 0 °C. The corresponding Michael adducts bearing a new stereocenter were obtained in high yields and with enantioselectivities of up to 80%. Theoretical calculations are used to justify the observed sense of the stereoinduction.

Enantioselective Michael addition of aldehydes to maleimides organocatalysed by chiral 1,2-diamines: an experimental and theoretical study

Simple and commercially available chiral 1,2-diamines were used as organocatalysts for the enantioselective conjugate addition of aldehydes, including α,α-disubstituted, to maleimides. The reaction was carried out in the presence of hexanedioic acid as an additive in aqueous solvents at room temperature. By employing (1S,2S)- and (1R,2R)-cyclohexane-1,2-diamine as organocatalysts, the corresponding Michael adducts bearing new stereocenters were obtained in high or quantitative yields with enantioselectivities of up to 92%, whereas the use of (1S,2S)-1,2-diphenylethane-1,2-diamine gave a much lower ee. Theoretical calculations were used to justify the observed sense of the stereoinduction.

Enantioselective Synthesis of Succinimides by Michael Addition of Aldehydes to Maleimides Organocatalyzed by Chiral Primary Amine-Guanidines

The monoguanylation of (1S,2S)- and (1R,2R)-cyclohexane-1,2-diamine affords chiral primary amine-guanidines that are used as chiral organocatalysts in the enantioselective Michael addition of aldehydes, particularly α,α-disubstituted aldehydes, to maleimides. The reaction is carried out in the presence of imidazole, as an additive, in aqueous N,N-dimethylformamide, as the solvent, and affords the corresponding enantioenriched succinimides in high or quantitative yields with enantioselectivities up to 96 % ee. Theoretical calculations (DFT and M06–2X) suggest a different hydrogen-bonding coordination pattern between the maleimide (C=O) and the catalyst (NH groups) is responsible for the enantioinduction switch that is observed when the reaction is carried out using primary amine-guanidines versus primary amine-thioureas as the organocatalysts.

Efficient Diastereo- and Enantioselective Synthesis of exo-Nitroprolinates by 1,3-Dipolar Cycloadditions Catalyzed by Chiral Phosphoramidite⋅Silver(I) Complexes

Chiral complexes formed by privileged phosphoramidites and silver triflate or silver benzoate are excellent catalysts for the general 1,3-dipolar cycloaddition between azomethine ylides generated from α-amino acid-derived imino esters and nitroalkenes affording with high dr the exo-cycloadducts 4,5-trans-2,5-cis-4-nitroprolinates in high ee at room temperature. In general, better results are obtained using silver rather than copper(II) complexes. In many cases the exo-cycloadducts can be obtained in enantiomerically pure form just after simple recrystallization. The mechanism and the justification of the experimentally observed stereodiscrimination of the process are supported by DFT calculations. These enantiomerically enriched exo-nitroprolinates can be used as reagents for the synthesis of nitropiperidines, by ester reduction and ring expansion, which are inhibitors of farnesyltransferase.

Enantioselective Synthesis of exo-4-Nitroprolinates from Nitro­alkenes and Azomethine Ylides Catalyzed by Chiral Phosphor­amidite·Silver(I) or Copper(II) Complexes

Chiral complexes formed by privileged phosphoramidites derived from chiral binol and optically pure Davies’ amines, and copper(II) triflate, silver(I) triflate or silver(I) benzoate are excellent catalysts for the general 1,3-dipolar cycloaddition between nitroalkenes and azomethine ylides generated from α-amino acid derived imino esters. These three methods can be conducted at room temperature to afford the exo-cycloadducts (4,5-trans-2,5-cis-4-nitroprolinates) with high diastereoselectivity and high enantioselectivity. In general, the three procedures are complementary but silver catalysts are more versatile and less sensitive to sterically congested starting materials.

Pyrimidine-Derived Prolinamides as Recoverable Bifunctional Organocatalysts for Enantioselective Inter- and Intramolecular Aldol Reactions under Solvent-Free Conditions

Chiral L-prolinamides 2 containing the (R,R)- and (S,S)-trans-cyclohexane-1,2-diamine scaffold and a 2-pyrimidinyl unit are synthesized and used as general organocatalysts for intermolecular and intramolecular aldol reactions with 1,6-hexanedioic acid as a co-catalyst under solvent-free conditions. The intermolecular reaction between ketone–aldehyde and aldehyde–aldehyde must be performed under wet conditions with catalyst (S,S)-2b at 10 °C, which affords anti-aldols with high regio-, diastereo-, and enantioselectivities. For the Hajos–Parrish–Eder–Sauer–Wiechert reaction, both diastereomers of catalyst 2 give similar results at room temperature in the absence of water to give the corresponding Wieland–Miescher ketone and derivatives. Both types of reactions were scaled up to 1 g, and the organocatalysts were recovered by extractive workup and reused without any appreciable loss in activity. DFT calculations support the stereochemical results of the intermolecular process and the bifunctional role played by the organocatalyst by providing a computational comparison of the H-bonding networks occurring with catalysts 2a and 2b.

Synthesis of Chromen[4,3-b]pyrrolidines by Intramolecular 1,3-Dipolar Cycloadditions of Azomethine Ylides: An Experimental and Computational Assessment of the Origin of Stereocontrol

Azomethine ylides, generated from imine-derived O-cinnamyl or O-crotonyl salicylaldeyde and α-amino acids, undergo intramolecular 1,3-dipolar cycloaddition, leading to chromene[4,3-b]pyrrolidines. Two reaction conditions are used: (a) microwave-assisted heating (200 W, 185 °C) of a neat mixture of reagents, and (b) conventional heating (170 °C) in PEG-400 as solvent. In both cases, a mixture of two epimers at the α-position of the nitrogen atom in the pyrrolidine nucleus was formed through the less energetic endo-approach (B/C ring fusion). In many cases, the formation of the stereoisomer bearing a trans-arrangement into the B/C ring fusion was observed in high proportions. Comprehensive computational and kinetic simulation studies are detailed. An analysis of the stability of transient 1,3-dipoles, followed by an assessment of the intramolecular pathways and kinetics are also reported.

Primary Amine–2-Aminopyrimidine Chiral Organocatalysts for the Enantioselective Conjugate Addition of Branched Aldehydes to Maleimides

Chiral primary amines containing the (R,R)- and (S,S)-trans-cyclohexane-1,2-diamine scaffold and a pyrimidin-2-yl unit are synthesized and used as general organocatalysts for the Michael reaction of α-branched aldehydes to maleimides. The reaction takes place with 10 mol% organocatalyst loading and hexanedioic acid as cocatalyst in aqueous N,N-dimethylformamide at 10 °C affording the corresponding succinimides in good yields and enantioselectivities. DFT calculations support the stereochemical results and the role played by the solvents.

Enantioselective addition of aryl ketones and acetone to nitroalkenes organocatalyzed by carbamate-monoprotected cyclohexa-1,2-diamines

Enantiomerically pure carbamate-monoprotected trans-cyclohexane-1,2-diamines are used as chiral organocatalysts for the addition of aryl ketones and acetone to nitroalkenes to give enantioenriched β-substituted γ-nitroketones. The reaction was performed in the presence of 3,4-dimethoxybenzoic acid as an additive, in chloroform as the solvent at room temperature, achieving enantioselectivities up to 96%. Theoretical calculations are used to justify the observed sense of the stereoinduction.

Solvent-Induced Reversal of Enantioselectivity in the Synthesis of Succinimides by the Addition of Aldehydes to Maleimides Catalysed by Carbamate-Monoprotected 1,2-Diamines

A simple change in the polarity of the solvent allows both enantiomers of substituted succinimides to be obtained in the enantioselective conjugate addition reaction of aldehydes, mainly α,α-disubstituted, to maleimides catalysed by chiral carbamate-monoprotected trans-cyclohexane-1,2-diamines. Using a single enantiomer of the organocatalyst, both enantiomers of the resulting Michael adducts are obtained in high yields by simply changing the reaction solvent from aqueous DMF (up to 84 % ee) to chloroform (up to 86 % ee). Theoretical calculations are used to explain this uncommon reversal of the enantioselectivity; two transition state orientations of different polarities are differently favoured in polar or nonpolar solvents.